In wireless communication systems, it is sometimes desirable to manage Quality of Service (QoS) for traffic on a connection between a cellular device and a server acting as a gateway towards a communication network. The communication network is external to the wireless communication system. The QoS relates to requirements for the traffic. Examples of requirements for the traffic include bit rate, delay and the like. The QoS can be managed on a per subscriber level, e.g. per cellular device, a per subscriber group level, e.g. premium users may get special benefits in terms of e.g. bit rate. Some known wireless communication systems are described by the Third Generation Partnership Project (3GPP).
An overview of a 3GPP Long Term Evolution (LTE) network is illustrated in FIG. 1. The 3GPP network comprises a Core Network (CN) 11 and a Radio Access Network (RAN) 12. An external communication network 13 is exemplified by the Internet. The core network 11 comprises a Serving GateWay 20 (SGW), a Packet Data Network GateWay 21 (PDN GW), a Policy Charging and Rules Function (PCRF) 22 and a Mobility Management Entity (MME) 23. The radio network 12 comprises an eNB 31 and a radio device 32, or User Equipment (UE).
In 3GPP, QoS is managed on a per bearer level from the Core Network 11. The RAN 12 is responsible for setting up a radio bearer 41, radio resource management, and enforcing QoS according to a bearer QoS profile over the radio interface, e.g. LTE-Uu, in the downlink, i.e. towards the radio device 32, and over the core network 11 in the uplink, i.e. towards the Internet 13. In this overview of 3GPP LTE network, the QoS framework is illustrated. An Evolved Packet System (EPS) bearer 51 including a QoS profile is set up from the PDN GW 21 in the CN 11, and QoS is enforced in the PDN GW 21 and in the eNB 31 for the downlink, and in the radio device 32 and the eNB 31 for the uplink. In somewhat more detail, this means that the EPS bearer is built up by the radio bearer 41 and a S1 bearer 61. The S1 bearer 61 carries traffic between the eNB 31 and the PDN GW 21. Notably, the QoS profiles of the radio bearer and the S1 bearer are typically derived from the QoS profile of the EPS bearer. The EPS bearer may be referred to as a Non-Access Stratum (NAS) bearer and the radio bearer combined with the S1 bearer may be referred to as an Access Stratum (AS) bearer in case the LTE network is a generic telecommunication system. It shall also be said that the SGW 20 communicates with the PGW 21 via an S5/S8 interface 71 and that the SGW 20 communicates with the MME 23 via an S11 interface 81.
Many services and radio devices share the same radio and network resources. Real-time services, such as voice, video etc., are sharing the same resources as non-real-time services, such as Internet browsing, file download etc. One challenge in this area is how to ensure QoS (bit rates, packet delays, packet loss) for the Real-time services. 3GPP EPS provides efficient QoS mechanisms to ensure that the user experience of different services sharing the same resources is acceptable. Examples of the QoS mechanisms are:                1 Traffic Separation; different traffic types receive different treatment, such as queuing, priority, etc., in network,        2 3GPP provides for both relative QoS and absolute QoS, where absolute QoS uses Guaranteed Bit Rates (GBR),        3 GBR based admission control is used to reserve resources before traffic is admitted into the network or rejected otherwise        4 Policy and Charging Control (PCC) determines what treatment to apply to various traffic streams        
3GPP discusses a concept referred to as a Packet Data Network (PDN). A PDN is in most cases an Internet Protocol (IP) network, e.g. Internet or an operator IP Multimedia Subsystem (IMS) service network. A PDN has one or more names; each name is defined in a string called Access Point Name (APN). A PDN GateWay (PGW or PDN GW) is a gateway towards one or more PDNs. A UE may have one or more PDN connections. A PDN connection is a logical IP tunnel between the UE and the PGW, allowing the UE to access a PDN of the PGW. The setup of a PDN connection is initiated from the UE.
Every PDN connection consists of one or more bearers as outlined above. See 3GPP TS 23.401 section 4.7.2 for a description of the EPS bearer concept. A bearer uniquely identifies one or more traffic flows, i.e. streams of traffic carried by the bearer. This means that the traffic flows receive the same QoS treatment between the UE and the PGW, when the traffic flows are carried by the same bearer. The EPS bearer is end-to-end between UE and PGW. Every PDN connection has at least one EPS bearer and this EPS bearer is called the default bearer, e.g. the default EPS bearer. All additional bearers on the PDN connection are called dedicated bearers, e.g. the dedicated EPS bearers.
Within the dedicated EPS bearers, there are two types of bearers: GBR and non-GBR bearers. Every EPS bearer is associated with the following QoS parameters: QoS Class Identifier (QCI) and Allocation and Retention Priority (ARP). GBR bearers are in addition associated with bit rate parameters for GBR and Maximum Bit Rate (MBR). Non-GBR bearers do not have bearer-level bit rate parameters. Instead, there is aggregate enforcement of all non-GBR bearers using Aggregate Maximum Bit Rates (AMBR) (APN-AMBR: defined per subscriber and APN, and UE-AMBR: defined per subscriber).
With reference to FIG. 2, a procedure for activating, or setting up, a dedicated bearer with a specific bearer QoS in a 3GPP EPS/LTE network is shown. See also 3GPP TS 23.401, section 5.4.1. The procedure is initiated by the PDN GW with input from the PCRF providing the PDN GW with an updated QoS profile. In case the PCRF is not deployed, the QoS is set locally by the PDN GW. The Figure shows dedicated bearer activation and similar steps are taken for the initial configuration of the default bearer in relation to UE attach to the network.
In FIG. 3, a procedure for modifying a bearer with bearer QoS update is shown. See also 3GPP TS 23.401, section 5.4.2.1. The procedure is initiated by the PDN GW with input from the PCRF providing the PDN GW with an updated QoS profile. Again, in case the PCRF is not deployed, the QoS is set locally by the PDN GW. This procedure is triggered every time QoS must be updated. QoS enforcement points are typically in PDN GW, eNodeB and UE.
It is worth mentioning that the procedures of FIGS. 2 and 3 are performed in the case QoS for a specific UE and bearer(s) needs to be updated. The signaling flow in FIG. 2 can be used to initially set a QoS profile and the signaling flow in FIG. 3 can be used to change the initial QoS profile to another QoS profile.
3GPP QoS is typically configured and managed from the PDN-GW, and supported by the PCRF, if deployed in the CN. When a traffic flow for a UE meets any criteria for updating its QoS treatment, an update of the present bearer QoS profile is done through the PCRF, and the bearer update is signaled to all the impacted network nodes, including the User Equipment (UE). A UE can have several bearers that all need to be updated. The amount of signaling can be significant depending on the number of bearers that need to be updated, and the number of, and frequency of users that require updated QoS.
In one example, a plurality of enterprise users enters or leaves an enterprise venue. The enterprise users may belong to a so called Closed Subscriber Group (CSG), for which there has been deployed dedicated base stations within the enterprise venue. Every time the enterprise users enters or leaves the enterprise venue, they will get updated QoS. The updating of QoS can produce large amounts of signaling. Additionally, a surrounding macro system, intended to serve any user outside the enterprise venue as well as non-enterprise users within the enterprise venue, may leak into the enterprise venue. Thus, additional handovers and QoS updates are provoked and additional signaling for QoS updates follows. The large amount of signaling may degrade performance of the EPS/LTE network.